Plant-based diets are gaining increased attention for their potential role in reducing cancer risk and supporting patients during treatment. Emma Veilleux, senior dietitian with the Simms/Mann UCLA Center for Integrative Oncology, shares insights into how a well-planned plant-based diet can make a big difference
Understanding plant-based diets
A plant-based diet emphasizes fruits, vegetables, legumes, grains, nuts, seeds, and herbs. Though the definition of what a plant-based diet is may vary, Veilleux focuses on a diet that is entirely plant-derived, without any animal products.
She explains that such diets should focus on whole, minimally processed foods, which can help limit intake of saturated fats, sodium, and added sugars.
“You can still eat a cancer-preventive diet as a vegan, vegetarian, or omnivore,” she adds, “if you’re eating predominantly whole plant foods and limited processed foods or high-fat animal products
Plant-based diets and cancer prevention
The link between plant-based diets and cancer prevention is rooted in the array of phytochemicals found in plant foods. Phytochemicals, such as sulforaphane, a compound found in cruciferous vegetables like broccoli and Brussels sprouts, have been shown to inhibit cancer cell growth.
“There is lots of research to support that many phytochemicals — beneficial compounds only found in plants — are protective from a cancer reduction standpoint,” Veilleux says.
Fiber is another essential component in reducing cancer risk. Found only in plant foods, fiber supports digestion, blood sugar regulation, cholesterol management, and weight maintenance — all factors contributing to reduced cancer risk.
“Outside of phytochemicals, fiber is the nutrient found only in plants that has the most important role in terms of reducing cancer risk,” Veilleux says.
Benefits during cancer treatment
A plant-based diet can be tailored to support the specific nutritional needs of individuals undergoing cancer treatment. Veilleux notes that while a plant-based diet isn’t necessarily more nutritionally beneficial than others, it can effectively meet nutrient needs if properly planned.
Cancer treatments, such as chemotherapy, can cause side effects such as diarrhea, which may require diets to be adjusted. Some plant-based foods may help with specific side effects, such as nausea or fatigue, though these preferences are highly individualized.
Nutritional considerations for people with cancer
Transitioning to a plant-based diet requires attention to nutrients that are more readily found in animal products. Protein, iron, calcium, zinc, and omega-3 fatty acids, though present in plant foods, require careful selection to meet daily needs.
“All people who eat a plant-based diet need to supplement with vitamin B12, as this nutrient is not naturally available from plant foods,” Veilleux advises. Vitamin B12 plays a key role in the production of red blood cells and ensuring cells carry oxygen efficiently.
Working with a dietitian can help patients manage these potential gaps and ensure balanced nutrition during treatment. A dietitian can help determine appropriate intake levels for specific nutrients and suggest tests if a deficiency is suspected.
“Lab tests can shed light on whether a person needs to take a supplement or be extra diligent about obtaining that nutrient from food,” Veilleux says.
Challenges and practical tips for changing diet
Shifting to a plant-based diet while managing cancer can be challenging. Patients may feel restricted without familiar animal products, and cancer treatments can alter appetite and taste preferences.
To ease the transition, Veilleux suggests keeping a variety of plant-based foods on hand. Nutritious items such as non-dairy yogurt are increasingly accessible and can provide familiar textures and flavors. At the same time, diverse plant-based options such as pre-made protein shakes, nuts, nut butters, and tofu also can help provide the necessary nutrients.
For those new to plant-based eating, there are numerous resources. Veilleux points to organizations such as the Academy of Nutrition and Dietetics, the American College of Lifestyle Medicine, and the American Institute for Cancer Research as reliable sources for guidance on plant-based diets.
Veilleux recommends recipe blogs, such as Forks Over Knives and Vegetarian Times, that can offer practical, approachable meal ideas.
Limitations and future research
Evidence already supports the connection between plant-based diets and reduced cancer risk, but future research may fine-tune specific recommendations on how certain fruits and vegetables specifically lower cancer risk.
“Fruits and vegetables are the stars,” says Veilleux, who expresses optimism about studies that will refine the understanding of how plant-based foods can influence cancer outcomes.
Conclusion
A plant-based diet, rich in whole foods, offers promising benefits for cancer prevention and can be tailored to support individual nutritional needs during treatment. Consulting with a dietitian can help patients navigate potential nutritional gaps and customize a diet that aligns with their treatment journey.
As research evolves, plant-based diets are likely to remain a promising tool both for the prevention and treatment of cancer.
Learn more about Nutritional Support for Cancer Patients and see some suggested recipes
